Prospective pilot study of sildenafil for treatment of postradiotherapy erectile dysfunction in patients with prostate cancer

Purpose: Erectile dysfunction is a common late complication patients may ex perience after external-beam radiotherapy for prostate cancer. The efficacy and safety of oral sildenafil to correct sexual dysfunction caused by exte rnal-beam radiotherapy was studied in patients participating in our prospec tive trial. Patients and Methods Thirty-five assessable patients participated in this p rospective pilot study. Using a 25-point scale based on the International i ndex of Sexual Function, erectile dysfunction was assessed weekly, during w hich time patients received sildenafil 100 mg orally once a week for 6 cons ecutive weeks. Response was defined as a score of 18 or more, corresponding to at least one successful attempt at sexual intercourse per week, Results: Thirty patients (86%) completed the 6-week study Seventy-seven per cent of these patients had significantly improved erectile function, allowi ng recovery of full capacity for sexual intercourse, Of 27 patients not rec eiving concomitant hormone treatment, failure to respond wets observed in o nly four patients (15%) compared with four (50%) of eight patients receivin g hormonal treatment during the study, The time course of response was grad ual, with 40%, 57%, 66%, 69%, and 74% responding at weeks 1 through 5, resp ectively. Therapy was generally well tolerated. The most frequently reporte d side effects in patients were flushing (37%), transient headache(17%), an d dyspepsia (9%). No patient reported priapism, and no cardiovascular event or death was observed. After response, 12 patients (34%) reported the abil ity to achieve and maintain an erection sufficient far intercourse in the a bsence of sildenafil (ie, 24 hours to 6 days after taking the medication). Conclusion: This study suggests that oral sildenafil is well tolerated and can reverse erectile dysfunction after radiotherapy in a substantial propor tion of prostate cancer patients. (C) 1999 by American Society of Clinical Oncology.